Sanserino just posted the news to the PBC blog (reprinted here for those of you who don't pay for PG+):

INDIANAPOLIS – Pirates outfielder Alex Presley and infielder Chase d’Arnaud are being activated from the disabled list and will rejoin the team Thursday in St. Louis.
The team will likely announce the move Thursday, once both players arrive in St. Louis. The team will then announce a corresponding move to make room on the 25-man roster.
Presley and d’Arnaud were taken out of the Class AAA Indianapolis starting lineup two hours before first pitch tonight. They will fly to St. Louis on Thursday morning.

I'm stoked. I'm sure this will end the latest chapter in the Pedro Ciriaco saga, and I guess this means Aaron Thompson goes back to Indy as well. Not that I really think he should stay up, but it's an unceremonious demotion after a helluva start today. That's baseball. I can't wait to see Presley back in our lineup tomorrow night.